Really, I was shocked that blu-ray would never remember where I was in a movie to resume watching later. It seems like such a simple thing to be able to do instead of starting over each time.
I am serious. The BD-J disks which now comprise the great majority will simply not permit a “resume” function. It you stop the disk, you must start from the very beginning. You can pause it and then continue (but most players will automatically stop after 10 minutes or so), but you cannot stop. Makes it difficult to watch part of a film and then continue the next day without a lot of hassle. This is why I have abandoned blu-ray until this is fixed.
There are many discussions of this problem on-line. here is one: http://www.handcoding.com/archives/2009/04/03/oh-so-thats-why-some-blu-ray-discs-dont-resume/
That’s if you turn off the player, I think. You can certainly pause movie for as long as you want.
I’ve never had that happen to me with my PS3.